Cooling Fan Internals

[SD1too]

Thanks for the data on the PWM waveform Jules.

On your other point:

Originally Posted by Jules

Again I would stress NOT to apply ... earths on signal wires on diesels ...

As I've said, PCBs with blue/red signal wire and grey trinary switch wire on the same terminal do exactly that, by design I'm told by you and others! When the medium pressure trinary switch closes it connects the grey wire to earth. Therefore the blue/red signal wire is also at earth. I therefore don't understand what you're saying. It must be safe to apply an earth to the blue/red & grey parallel connection. I agree that this doesn't apply to PCBs where the blue/red and grey wires are separately connected. Is that what you meant to say?

Regards,

Simon.

[Billy1mate]

I don't think it has been tampered with before, previous owner said the aircon worked but I bought it in February so aircon might have worked without the fan. They had the car for 5 years. Previous chap had it from new. Only tinkering is me, trying to get it back to where once it was.

Red/blue from pcb to [B]C0331 pin 4[B] continuity checked, all fine.

[SD1too]

Ade,

I need your answer to my post no. 70.

Simon.

[Billy1mate]

O.K. Ade, this is what we do. Locate the trinary switch and remove the connector. With care, join together the terminals on the wiring connector fed by the black/red (pin 1) wire and the red/black (pin 4) wires (the second colour is the tracer). Turn on the ignition and press 'demist'. Does anything happen?





Sorry Simon, I did this and nothing happened.

[SD1too]

O.K., I'm not really clear on what exactly you did, but on the assumption that you definitely did this first:

Originally Posted by Billy1mate

Trinary switch shorted between yellow & red/black, ign on, demist selected ...
Fan runs up, relay in control box goes tick, tick....tick, tick.....
And so on.
After about 10 seconds, ticking stopped & so did the fan.

You might have damaged components on the PCB because you didn't observe the correct wiring colours. The fan probably stopped due to this failure.

On the assumption that you subsequently repeated the test with the correct colours and:

Originally Posted by Billy1mate

... I did this and nothing happened.

... probably means that you have created a fault on the PCB. The test was designed to simulate a correct charge of refrigerant in the air conditioning system (it might be too low or too high) which should have caused the compressor clutch to engage (a loud clunk) and the fan to run.

I recommend that you fit your original PCB to the control box, keeping the connections the same as they were originally i.e. grey to it's own terminal and blue/red to it's own terminal (not joined together on one terminal). Refit the trinary switch connector, turn the ignition on and press 'demist'.

Does the compressor clutch give a loud clunk as it engages?
Does the fan run at slow speed?

Simon.

[Arctic]

Originally Posted by SD1too

Morning Ade,

I've reviewed your whole story and there's one thing which I'd like you to clarify. After looking at Arctic's photos you said this:

I'm interested in this other grey wire. I understand that one end of this loop is connected to the thin grey wire leading to the control box. Is the other end of the loop connected to another wire or does it just go to a connector pin and stop there?

I'd also like to check again that the PCB is earthed. With the ignition off and with your meter on a low resistance range, can you check continuity between the thin black wire on the small middle relay and the battery negative terminal?

If nothing emerges from this, I'm going to suggest that you fit your original PCB (the one used with your failed 3 speed, 4 wire motor) into the current control box (the one from e-bay). My reasoning is that your original set up failed because of worn motor brushes, so it is reasonable to expect the PCB to be o.k. When swapping, use the relays which we proved yesterday are working (label them so that they don't get mixed up with any others).

Simon.

Originally Posted by Billy1mate

hopefully here are some photos.

My original did have separate connections for the blue/red and grey wires

the blue/red wire from the car's loom does go to the blue wire on the pcb/ control box. (photo 3)

I've been thinking that there may be an ECU snag.

Hi Lads
Have managed to get on the PC and have a read of this as to where you are now and i agree with simon use you old original PCB and set it up with the gray wire to its own terminal i recently went to a members house after he called me he could not get his fan to work even after fitting two new gold resistors and changing the relays.
We decided in the end to fit one of my gold resistors his original relays and a PCB i bought with me from a three speed four wire control box woosh it worked straight away.

So put your old PCB back in the control with relays but make sure the grey wire goes to its own terminal on the PCB pics below some mine and i think one of Jules of a new fan motor note how its wired

Ade 1-2-3
1

2

3

Arctic 4-5-6
4

5

6

Jules?


Note how the wires are in the old three speed and the two speed in pis 6
Arctic.

[Billy1mate]

Oh chuff, I've put the car back together, I was going to extend the wires to remotely locate the control unit but I between painting and visitors arriving, the day went. I will do it soonest though.

[Billy1mate]

Happy New Year & a big thank you to all of you who replied to this post. It has not reached a conclusion until now, (good job none of you held your breath.)
After a T4 session it was concluded that the IPK was not talking to the ECU hence no HRW, rev counter & temp gauge but more importantly no fan or A/C.
So a replacement ECU set up by MarinaBrian and everything is working as it left the factory. Hopefully this can be of benefit to others.

[stocktake]

Originally Posted by Billy1mate

Happy New Year & a big thank you to all of you who replied to this post. It has not reached a conclusion until now, (good job none of you held your breath.)
After a T4 session it was concluded that the IPK was not talking to the ECU hence no HRW, rev counter & temp gauge but more importantly no fan or A/C.
So a replacement ECU set up by MarinaBrian later and everything is working as it left the factory. Hopefully this can be of benefit to others.

Every now and again a thread like this appears and it makes me realise just how little I know about these cars, my hat is off to all the boffins who work for hours on end for nothing more than the knowledge that it will help somebody some where some day. Particularly the T4 crew not only on here that now collectively must know more than the tech boffins at Rover knew themselves